Concentration of ores



Patented a... 13, 1939 UNITED STATES 2,162,495 PATENT? OFFICE 2.10am; concur-mums or oats William Trotter,

W Berkeley,

San Francisco, and Eltoit Wray Calif. assilnors to Minerals s'eparation North American Corporation, New York, N. Y., a corporation of Maryland No Drawing. Original application August 20,

1934; ml N0.

Divided and this application January 24, 1938, Serial No. 180,586

The process 01 the present invention has proved especially useful in concentrating phosphatebeari'ng ores. .j In accordance with the invention, ores are concentrated by procedures involving their admixture -with a non-frothing organic liquid immiscible with water, such as iuel oil, and a thiocarbonic acid derivative containing the'residue of an aliphatic alcohol 01' at least twelve carbon atoms.

, Such organic-substituted compounds may, for example, be alkali metal andallraline earth metal xanthates of the stated number of carbon atoms in the hydrocarbon radical contained therein. The aliphatic alcohols capable oi use in producng the organic-substituted compounds of the present invention may be normal primary alcohols, but other types of alcohols may also be used. The organic-substituted or hydrogen-replacing groups in these compounds thus not only comprise simple alkyl radicals, but may also consist centration of sulphides and other metallic minof the residues of unsaturated oleflnic alcohols. Examples of organic-substituted compounds which may be used in the process of the present invention are alkali metal and alkaline earth metal salts of xanthic acids containing the alcohol radicals lauryi, cetyl, myristyl, oleyl, etc.

Instead of thiocarbonic acid derivatives, it has also been found possible to employ with nonfrothing water-immiscible organic liquids derivatives of phosphoric acid similarly containing allphatic alcohol residues of at least twelve carbon atoms, e. g., the acid esters of phosphoric acid with such alcohols as lauryl, cetyl, myristyl, and

' oleyl alcohols, as well as the alkali metal andalkaline earth metal salts of such acid esters. However, the claims of thisapplication do not cover the use with non-irothing water-immiscible organic liquids of these phosphoric acid derivatives, whichare separately claimed in our'aiorementioned application Ser. No."740,600.

Many non-irothing organic liquids, substantially insoluble in or immiscible with water in the proportions used, maybe employed to carry out;

the process of the present invention by cooperating with the organic-substituted compounds herein described. Such liquids contain no substantial amounts of free fatty acids. Such widely varyingtypes of non-frothing substantially waterimmiscible organic' liquids as fuel oil, kerosene, dipentene (a terpene hydrocarbon), crude sol-- -vent naphtha (from coal tar), water gas tar, and carbon tetrachloride have proved useful in carryhis out the processor the present invention.

1': Claims. (Ci. zoo- 106? n Fuel oil, however, onaccount oi its low cost, is generally preferred.

The organic-substituted compounds used in the process of the present invention have certain characteristics of soap and are in general capable of operating as irothing agents. However, the

principal function of the organic-substituted compounds used in theprocess oi the present inventionis to make the non-frothing water-immiscible organic liquids also used eilective by causing those liquids to adhere selectively to the mineral values in the ore.

The use of xanthates and other. thiocarbonic acid derivatives in the flotation concentration of sulphide and other metallic minerals is well known in the art. And we are well aware of the,

fact that in these prior processes the efficiency of such compounds becomes less as the number of carbon atoms included in the alcohol employed in their preparation increases to more than about seven. On the other hand, it has been found, that, in order to be useful in the process of the present invention, xanthates and other thiocarbonic acid derivatives must have twelve or more carbon atoms in their alcoholic radical. The "lower organic-substituted thio-carbonic acid compounds which are best in the flotation coneralsare of no value whatever in the process of the present invention. I

The organic-substituted compounds used in the process 01' the present invention need not be pure compounds. For instance, the alcohols usedin making them may be of commercial grades containing substantial amounts or other alcohols, which results in the production of mixtures of organic-substituted compounds of varying carbon employed to contribute their own peculiar prop-- erties,'such as irothing ability, DH-control, etc.,

wherebythe best conditions for the exercise of the intended functions of the organic-substituted compounds herein described and their cooperating non-irothing waterdmmiscible organic liquids may be obtained.

Incarrying out the process of-the present invention, addition to the oreoi'the various reagents used may be made with the ore eithervin a state of dryness or in the form of an aqueous pulp. In either case,'of course, the subsequent have been found useful, which include froth flothen added 13 lbs. per ton of fuel oil.

- 85.5% caco: and 8.2% insolubles.

tation, tabling, and hydraulic classification.

In preparing the ore for treatment by the process of the invention, it is in general desirable that it be largely deslimed, its desliming greatly minimizing the consumption of the agents used, improving the results obtained, and rendering the process commercially practicable. In most cases, the crude ore is first subjected to a preliminary grinding operation, after which slimes are removed.

Examples will now be given describing certain tests which have been made in carrying the invention into effect, it being understood that the reagent proportions indicated in each example are expressed in the'usual manner as pounds per ton (2000 lbs.) of dry material treated.

Example 1.Valley Forge Cement Company classifier overflow, consisting mainly of finely crushed limestone and silica, was mixed with 2.2 lbs. per ton of potassium cetyl xanthate dissolved in water, the quantity of water beingsuch as to produce a pulp of 45% solids. Tothis pulp were After thorough mixing, the pulp was thinned and frothed in a laboratory-size subaeration flotation machine, another 2.2lbs. per ton of potassium cetyl xanthate being added after about one minute of froth removal, the total period of which was about two minutes. The heads contained 74.1% CaCO; and 20.26% insoluble matter; The concentrates carried 55.0% of the total calcite content of the heads in a product containing In each of the following six examples, Florida phosphate ore, screened to pass 20-mesh and deslimed, was first mixed dry with fuel oil and thereafter mixed dry or in a thick pulp with an alkali metal xanthate. The mixture'was then diluted and the B. P. L. values '(tricalcium phosphate) removed therefrom by flotation. The material floated in these tests was either of the nature gf'atfroth or of the nature of a heavy flocculated Examp e 2.'For the purpose of this test, potassium cetyl xanthate was used to cooperate with the fuel oil, the above-mentioned phosphate ore being treated" with these agents in the amounts of 1.5 lbs. per ton of the xanthate and 11.2 lbs. per ton of, the fuel oil. From heads containing 27.8% B. P. L., concentrates assaying 7 B. P. L. and tailings 10.2% were obtained, representing a B. P. L. recovery of 72.9%.

Example 3.--In this test, using 2 lbs. per ton of potassium myristyl xanthate and 11.2 lbs. per ton of fuel oil, the concentrates assayed 73.6% B. P. L. and the tailings 6.6%. The heads contained 27.3% B. P. L., the recovery being 83.3%.

Example 4.'When 1.5 lbs. per ton of potasslum myristyl xanthate and 9.4 lbs per ton of.

fuel oil were used instead of the larger amounts, the B. P. L. assay of the concentrates was 75.8% and thatof the tailings 9.6%. The B. P. L. re-

covery was 74.1%, the content of the heads being 27.2%.

Example 5.In this instance, using 2 lbs. of potassium laurylxanthate and 24.4 lbs. of fuel oil, both per ton, concentrates assaying 74.0% B. P. L. and ta iling"11.0% .were obtained from heads of 26.5%, the recovery being 68.7%.

Example 6.--With the amount of potassium lauryl xanthate increased to 2.5 lbs.'per tonand 2,162,496 a step of separating the mineral values is carried that of fuel oil decreased to 20.5 lbs. per ton,

the concentrates assayed 74.0% B. P. L and the' tailings 7.8%, representing a B. P. L. recovery of 79.6%, the content of the heads being 27.1%.

Example 7.For this test, 1.5 lbs. of potassium oleyl xanthate and 11.2 lbs. of fuel oil, both per ton, were employed. The heads contained 26.4% BLP. 'L., the concentrates 74.4%, and the tailings 512%, representing a B. P. L. recovery of 86.4%. I

Example 8.Another lot of the same deslimed phosphate ore was oiled dry with 11.2 lbs. per ton of fuel oil and 2 lbs. per ton of potassium myristyl xanthate, wetted to a thick pulp, mixed with more water to form a freely flowing pulp, and subjected to concentration on a Wilfley table, the phosphate values coming oi the side of the table and the tailings coming off the end.

The concentrates came oil partly as a surface Percent Percent Percent weight si f fi. '62:?

Example 9.--In this test, a xanthate containing an alkyl group with twelve carbon atoms proved useful 0n the highly refractory oxidized lead-silver ore of Naica mines of Mexico. This ore, ground to pass 48-mesh and then deslimed, was added to a little more than its own weight of water containing 3 lbs. of potassium lauryl xanthate per ton of 'ore. Thereafter, there were Iadded 14.9 lbs. per ton'of fuel oil, stirring being carried out for one-quarter minute. The

resulting mixture was then diluted and concentratesremoved by flotation. Another 3 lbs. per ton of potassium lauryl xanthate was added to the remaining pulp, admixture carried out, and further concentrates removed by flotation. These were added tov the first concentrates, the combined concentrates being then subjected to flotation so as to separate a final product of concentration therefrom. A middlings product was also obtained by this last operation, which was carried out without addingfurther agents. The results of the test were as follows:

Example 10.-Another lot of the same ore, also of 46-mesh and nearly deslimed, was added to a arcane 7 little -more than its own weight of water con taining potassium oleyl xanthate at the rate of 3 lbs. per ton of the ore. The mixture was then stirred in a flotation'machine for one-fourth minute with an added 14.9 lbs. of fuel oil per ton of the ore, diluted, and agitated for a removal of 1st concentrates. Two pounds more. per ton, of the same xanthate were added to the remaining pulp, admixture carried out, and

"2nd concentrates removed. In this test, the

heavily oiled floating material was held up partfollowing table:

' Assays Distribution Percent Ag Pb Ag Pb oa/ton percent percent 100. 0 17. 77 12. 0! 1G). (I) 100. 0 10.1 95.88 32.8) 54.50 27.5 10. 7 31. 15 42. 40 18. 37. 7 79.2 6.00 5. as. 75 34.8

been better by varying the reagent amounts, these results being as follows:

Percent Percent Percent a WV B. Bi. 1;. PE

100.0 2a: 100.0 22. 2 72. 1 ea. 4 Tail: 77.8 11.9 36.0

Example 15.Here 10.8 lbs. per ton of pure I being r'eadily obtained with the following results:

Example 11 .-Evans Wallower zinc blende ore,

ground to pass 48-mesh and then deslimed, was first mixed dry with 11.2 lbs. per ton of fueloil and thereafter added to a little more than its own weight of Watercontaining 2 lbs. of potassium cetyl xanthate per ton of ore. The mixture was thoroughly stirred, after which it was diluted and subjected to flotation, a heavily flocculatedmat like float being removed. Without further agents, this float was retreated to yield a finished product of concentration and a middlings product. The following results ,were obtained:

Percent Percent Percent Zn weight Zn assay recovery 100. 0 5. Si 100. 0 7. 8 55. 2o 9 4. 3 10. oo 7; 8 87. 9 0. 14. 3

Example 12.When potassium. myristyl xanthate was substituted for the cetyl xanthate of I Example 11, the concentrates carried 55.0% zinc and the tailihgs 0.5%.

In each of the" following three examples a watereimmiscibleliquld other than fuel oil was employed.

Example KL-Florida phosphate ore; ground to pass 35-mesh and desllmed, was added to its own weight of water with 2.5 lbs. of potassium lauryl xanthate and 10.9 lbs. of xylol, both per ton of are. This mixture-was stirred for fifteen seconds, whereafter it was diluted and subjected to flotation, a well flocculated froth high in phosphate being removed. The results of the test are indicatedin the following table:

Example 14.-When' 29.6 lbsfper ton of carbon tetrachloride were used in place of the xylol of Example 13, all other factors being the same, a

fiocculent froth of the phosphate values was again produced, though the results might have Retreatment 'of the concentrates obtained in the last three examples would have raised their phosphate values.

While the foregoing examples describe tests carried out withpotassium compounds of xanthic acids, the sodium,'barium compounds are equally as effective in the process of the present invention. The barium and ammonium compounds are also useful in the process of the present invention, although the sodium and potassium compounds are preferred.

Having thus described certain embodiments of the invention, what is claimed is:

l. The process of concentrating ores which comprises admixing with the ore, in a suitably divided state and, relatively free from slimes, a non-frothing organic liquid immiscible with water and a derivative of. a thiocarbonic acid containing the residue of an aliphatic alcohol-of at least twelve carbon atoms; and separating in an aqueous pulp the mineral values from the ore.

2. The process of concentrating ores which comprises admixing with the ore,' in a suitably divided state and relatively free from slimes, a

non-rfrothing organic liquid immiscible with water and-a derivative of a thiocarbonic acid containing an organic radical of the class consisting of saturated and unsaturated straight-chain alkyl groups of at least twelve carbon atoms; and separating in an' aqueous pulp the mineral values from the are.

3. The process of concentrating ores which comprises admixing with .the ore. in a suitably divided state and relatively free from slirnes, a non-frothing organic liquid immisciblm'with water and a compound included in the class consisting of the alkali-metal and alkaline-earth metal salts of acids derived from thiocarbonic acids by replacing one of their hydrogen atoms with the residue of an aliphatic alcohol of at least twelve carbon atoms; and separating in an aqueous pulp the mineral values from the ore.

4. The process of concentrating oreswhich comprises admixing with the ore, in a suitably divided state and relatively free from slimes, a

grade without materially increasing the loss in an aliphatic alcohol of at least twelve carbon atoms; and separating in an aqueous pulp the mineral values from the ore.

5. The process of concentrating ores which comprises admixing with the ore, in a suitably divided state and relatively free from slimes, a non-frothing organic liquid immiscible with-water and a compound included in the class consisting of alkali-metal and alkaline-earth-metal xanthates containing as their hydrocarbon radicals the residues of saturated and unsaturated alcohols of at least twelve carbon atoms; and

, separating in an aqueous pulp the mineral values from the ore.

6. The process of concentrating ores which comprises admixing with the ore, in a suitably divided state and relatively free from slimes, a non-frothing organic liquid immiscible with water and an alkali-metal xanthate containing as the hydrocarbon radical therein a straight-chain alkyl group of at least twelve carbon atoms; and separating in an aqueous pulp the mineral values from the ore.

'i. The process of concentrating ores which comprises admixing with the ore; in a suitably divided state and relatively free from slimes, a non-frothing organic liquid immiscible with water and a compound included in the class consisting' of alkali-metaland alkaline-earth-metal ous pulp the non-metallic mineral values from the ore.

9. The process of concentrating phosphatebearing ores which comprises admixing with the phosphate-bearing ore, in a suitably divided state and relatively free from slimes, a non-irothing organic liquid immiscible with water and an alkali-metal xanthate containing as the hydrocarbon radical therein a straight-chain 'alkyl group of atleast twelve carbon atoms; and separating in an aqueous pulp the phosphate values from the ore.

10. The process of concentrating ores which comprises admixing with the ore, in a suitably divided state and relatively free from slimes, a non-frothing organic liquid immiscible with water and an alkali-metal salt of a xanthic acid containing as the hydrocarbon radical therein the residue of an unsaturated oleilnic alcohol of at least twelve carbon atoms. and separating in an aqueous pulp the mineral values from the ore.

11., The process oi concentrating non-metallic ores which comprises admixing withthe noncarbon radical therein the residue of an-jun'satw' rated olefinic alcohol at least twelve carbon atoms; and separating in an aqueous pulp the non-metallic mineral values from the ore.

12. The process of concentrating ores which comprises admixing a thick aqueous pulp, relax-- tively free from slimes, of suitably divided particles of the ore with a non-frothing water immiscible organic liquid and an alkali-metal xanthate containing as the hydrocarbon radical thereinqa straight-p-chain alkyl group of at least twelve carbon atoms; and separating the mineral values from the pulp.

13. The process of concentrating non-metallic ores which comprises admixing a thick aqueous pulp, relatively free from slimes, of suitably divided particles 01 the nonmetallic ore with a non-frothing water-immiscible organic liquid and an alkali-metal xanthate containing as the hydrocarbonradical therein a straight-chain alkyl group of at least twelve carbon atoms; and separating the non-metallic mineral values from the pulp.

14. The process of concentrating oreswhich comprises admixing with the. ore, in a suitably divided state and relatively free from slimes, a non-Irothing organic liquid immiscible with water and a compound of the following general formula:

wherein R represents the residue of a straightchain aliphatic alcohol 01 at least twelve carbon atoms and M represents hydrogen or an alkali metal or an alkaline earth metal; and separating in an aqueouspulp the mineral values from the ore.

15. The process of concentrating ores which comprises admixing with the ore, in a suitably divided state and nearly free from slimes, a nonfrothing organic liquid immiscible with water and an alkali-metal oleyl xanthate; and separating in an aqueous pulp the mineral values from the ore.

16. The process of concentrating ores which comprises admixing with the ore, in a suitably.

divided state and relatively free from slimes, a non-frothing organic liquid immiscible with water and an alkali-metal lauryl xanthate; and separating in an aqueous pulp the mineral values from theore. V

17. The process of concentrating ores which comprises admixing with the 'ore, in a suitably divided state and relatively free from slimes, a

non-irothing organic liquid immiscible with waten and an alkali-metal cetyi xanthate; and separating in an aqueous pulp the mineral values from the ore.

ELTOFT WRAY WILKINSON.

- CERTIFICATE OF' CORRECTION. V I Patent No; 2,162,185. June 1 ,19 9;

WILLIAM TROTTER, ET AL; f It is hereby ceztified that error abpeara 1n the printed specification of the above numbered patent requiring" cqrrection as follows: Page 1, first Y column, i1ne7, for "and. mid" read and; sa1 ne pa'gefsecondcolumn, linelfl, v fer the werds "liquids orgazg z lc" read orgenie liqizide; page 2:, second column, fl i hes end 28;,f for the-words' "the end of phrtly at"' 1:e?i pp.rt1y at the end.

of; page 3 second column, line 31, strike'ofit the commsl angi, Word barium";

and thatthesaiid'L'etters Patentshould be read with this c'orrectidn therein that the samel paey cbnfonn to the record of-the ease in the Patent Office. Signed and sealed this lat day .at August, A. D. 1959.

' 'Henry Arsdale, (Seal) Acting Commissioner-of Patents. 

